Network monitoring is good for business
What you need to keep customer networks running; free network management tools perform basic tasks on smaller networks but pay-for tools give you more data and customisation options.
The network is the backbone of any IT infrastructure, so downtime and performance bottlenecks now have a critical effect even on the smallest business. This makes it is doubly important to monitor network status and activity in order to identify the source of any issues, and predict where other problems are likely to occur because of capacity shortages or overutilisation. In some cases, free network management software can handle basic detection and monitoring tasks. But for larger, more complex networks that span multiple sites or use a range of devices and protocols, you’ll usually need more sophisticated applications and suites.
Fluke Networks’ Switch Port Monitor (fluke-networks-switch-port-monitor.software.informer.com) is a good example of the type of free tools available. The software is exceptionally easy to use, but offers relatively few features or customisable options. It does a basic job of monitoring small, single domain LANs, finding SNMP-enabled devices like routers and switches and displaying them in a list, requiring the administrator to know the IP address and community string of the device to be monitored.
Once added to a profile (separate profiles can be saved and displayed simultaneously using tabs within the interface), the software identifies each port and interface, whether it’s LAN or wide area network (WAN), for example, and splits wireless into a separate interface.
As well as indicating each port’s status (up or down) and its maximum speed in bits per second, it records and displays statistics which include cumulative inbound and outbound data packets and errors and a bar indicating current and peak inbound and outbound utilisation. A tiny degree of customisation allows you to make the screen tidier, showing only packets, errors or utilisation stats, for example, or combinations of the three, and the software can display a separate window for each switch if required.
Alerts are limited to displaying messages within the software console itself. These can be configured to activate when pre-determined thresholds have been reached; inbound/outbound utilisation, number of errors, and when the status of the switch has changed, such as if it has been turned off.
Network management specialist Spiceworks is about to bring out a free SNMP network management tool and there are several low-cost alternatives available. One is Switch Center Workgroup 1.5, a network management and monitoring application for managed switches and hubs supporting SNMP BRIDGE-MIB that discovers, monitors, maps and analyses network topology and pro-vides information on connectivity and performance.
What You Pay For
Almost all networking monitoring tools are able to poll SNMP enabled devices and assign traps to them, then collect data from individual interfaces such as operational status, discarded packets, error packets, and averages and peaks of incoming/outgoing traffic.
Whereas most free or low cost network monitoring tools limit their scope to a single domain or virtual LAN (VLAN), pay-for tools scale to perform discovery at much larger topologies spanning multiple offices and sites. They also monitor network traffic according to specific protocols, like IP, IPX and NetBIOS, detect and monitor more equipment.
Fluke’s Optiview Management Suite comes pre-installed on a dedicated appliance that automati-cally starts discovering devices and monitoring traffic as soon as it is plugged into the network. It categorises not just routers, switches, hubs and access points, but also servers, printers, VoIP de-vices (Cisco, Nortel, Avaya and Mitel) and other SNMP agents, splitting them into IPv6 and IPv4 subnets, virtual LANs (VLANs), VoIP and NetBIOS domains and IPX networks, detecting duplicate IP addresses and incorrect subnet masks and as well as devices which are no longer responding.
Axence nVision 4.5 is another application that not only maps network devices like switches and routers, but also printers, mail servers and SQL servers. Nimsoft’s monitoring solution (NMS) of-fers similar functions, polling alls SNMP enabled devices for status data and also unsolicited SNMP traps (those that aren’t assigned to specific devices as passive monitors), with Syslog monitoring for non-SNMP devices.
NMS also taps into the IP Service level Agreement (SLA) data stored on Cisco networking equip-ment, monitoring their availability, response time, latency and jitter, for example. A DHCP and LDAP probe monitors DHCP servers and LDAP directories, sending out alerts if pre-defined min-imum response times or record numbers are exceeded.
Reporting and Alerts
Commercial network management applications also offer a much larger degree of customisation when it comes to designing reports and configuring alert messages.
Fluke Networks’ Reporter tool integrates with Microsoft’s Visio mapping software to create graphical maps showing the links between servers, routers, hosts, switches and hubs for example, whilst Ipswitch WhatsUp Gold offers more than 100 pre-defined summary reports and provides viewing options either a list of devices or a graphical map.
The network discovery and visualisation, network monitoring, and alerts and reports modules in Axence nVision 4.5 provides interactive network maps that shows information flow between different devices that can help identify bottlenecks and when specific ports or devices are close to reaching their capacity. A graphical netflow traffic analyser is also one of the tools in Solarwinds Orion, which also offers an application performance monitor alongside network configuration management that gauges DNS, IMAP4, POP3 and MAPI status to report on the performance of applications such as Active Directory, Exchange, SQL Server and IIS. NMS displays hardware status data in graphical alarm consoles, and also produces performance and SLA reports that indicate whether network capacity and uptime is meeting requirements.
WhatsUp Gold provides multiple interfaces which administrators can log into to access data. One is a Windows application, the other a Web interface that provides access to the application (via HTTP or HTTPS). Using the browser also gives you mobile access from a smartphone or other portable device, and you can get alerts by text message as well as email.
Some applications provide access to knowledge libraries and community downloads of useful software tools already created by other users. WhatsUp Gold has an extensive MIB library of dif-ferent vendor’s devices and applications, for example, as well as an active script library that you can apply on specific networks. Orion also provides templates from its community content ex-change on thwack.com which administrators can download and apply to software already running on the network; you’ll find application templates at thwack.com/media/42/orion-apm-content/ and device templates at thwack.com/media/41/orion-ncm-content/ncm-device-templates/.
Many commercial software tools include functions above and beyond network management and monitoring, like inventories of network attached equipment and license management or deep packet inspection (DPI) that examines the content of data traffic in order to prioritise it. Few smaller businesses will need these options routinely, but you may want them in your arsenal for surveys, auditing and troubleshooting.
12 most recommended network monitoring tools
Useful network monitoring tools, including some specialist tools:
Testertools directory – networking tools
An extensive list of free networking tools:
10 open source network tools
If you’re not looking for tools with the option of support, check these open source alternatives:
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